#include <iostream>
using namespace std;

signed main()
{
    int n;
    cin>>n;
    int f[100000] = {0};
    for(int i=0;i<n;i++){
        int t;
        cin>>t;
        f[t]++;
    }
    for(int i=0;i<100000;i++){
        if(f[i]%2!=0&&i%2!=0)    cout<<i;
    }
    return 0;
}
